Abstract: The very diverse Liassic toxa have evolved from thorny, partly thorny and smooth oxeas. One toxon morphotype (Cricotoxon) evolved by reducing the rays of a criccalthrops. All steps of this development can be demonstrated from a cricale calthrops through a tripod, a triod to a cricale diactine. The liassic forcipes (both smooth and thorny or spiny morphotypes) were derived exclusively from smooth or thorny, curved diactines, but not from toxa. All lowermost Liassic forcipes display pointed ends, in the contrast to the Tertiary and Recent forcipes that have terminal umbrella-like structures. The oldest well dated toxa are known from the Upper Cambrian, the oldest forcipes from the lowermost Ordovician. However, they are missing from the Middle Ordovician to the Middle Triassic. Toxa re-appeared rarely in the late Middle Triassic, whereas transitional forms to forcipes appeared only in the late Upper Triassic, diverse forcipes in the lowermost Liassic. The gap in the occurrence of toxa and forcipes from the Middle Ordovician to the Middle Triassic and Upper Triassic respectively cannot be explained satisfactorily, yet. Several explanations for this phenomenon are possible: (1) Demospongiae with toxa and forcipes survived in a relic area. Regarding the very long time gap (more tha 200 my) from which toxa and forcipes are unknown, this explanation is improbable. (2) The two spicule morphotypes evolved iteratively and independently from the Lower Paleozoic forms during the Triassic and lowermost Jurassic respectively. (3) Incomplete rossil record. This problem exists for several fossil microscleres.